(Invited) Flexible, Stretchable and Healable Electronics

Abstract

Organic electronics, based on semiconducting and conducting polymers, have been extensively investigated in the past decades and have found commercial applications in lighting panels, smartphone and TV screens using OLEDs (organic light emitting diodes) technology. Many other applications are foreseen to reach the commercial maturity in future in areas such as transistors, sensors and photovoltaics. Organic electronic devices, apart from consumer applications, are paving the path for key applications at the interface between electronics and biology, such as in polymer electrodes for recording and stimulating neural activity in neurological diseases. In such applications, organic polymers are very attractive candidates due to their distinct property of mixed conduction: the ability to transport both electron/holes and ionic species. Additionally, conducting polymers offer the possibility to tune their surface properties (e.g., wettability or chemical reactivity) by changing their oxidation state, thus promoting or hindering the adhesion of biomolecules. This feature can be particularly useful for enhancing the biocompatibility of implantable electrodes. My talk will deal with processing and characterization of conducting polymer films and devices for flexible, stretchable and healable electronics. Self-healing electronic materials are highly relevant for application in biology and sustainable electronics. We observed mechanical and electrical healability of PEDOT:PSS thin films. Upon reaching a certain thickness (about 1 µm), PEDOT:PSS thin films damaged with a sharp blade can be healed by simply wetting the damaged area with water. The process is rapid, with a response time on the order of 150 ms. Significantly, by blending with other polymers, the films are transformed into autonomic self-healing materials without the need of external stimulation. This reveals a new property of PEDOT:PSS and enables its immediate use in flexible and biocompatible electronics, such as electronic skin and bio-implanted electronics, placing conducting polymers on the front line for healing applications in bioelectronics. References [1] S. Zhang, F. Cicoira, Water-Enabled Healing of Conducting Polymer Films, Adv. Mater. 29, 1703098, 2017. [2] Y. Li, X. Li, S. Zhang, L. Liu, N. Hamad, S. R. Bobbara, D. Pasini, F. Cicoira, Autonomic self-healing of PEDOT:PSS achieved via polyethylene glycol addition, Adv. Funct. Mater. 30, 2002853, 2020. [3] Y. Li, S. Zhang, N. Hamad, K. Kim, L. Liu, M. Lerond, F. Cicoira, Tailoring the Self-Healing Properties of Conducting Polymer Films, Macromol. Biosci. i2000146, 2020.